Seato treaty
Southeast Asia Treaty Organization Southeast Asia Treaty Organization SEATO's flag Map of SEATO members, shown in blue. AbbreviationSEATOFormation8 September 1954Extinction30 June 1977Type intergovernmental military alliance Headquarters Bangkok , Thailand Region served Southeast Asia Membership 8 nations Australia New Zealand Pakistan (including East Pakistan , now Bangladesh ) Philippines Thailand France United Kingdom United States States protected by SEATO 2 nations South Vietnam Kingdom of Laos The Southeast Asia Treaty Organization ( SEATO ) was an international organization for collective defense in Southeast Asia created by the Southeast Asia Collective Defense Treaty , or Manila Pact , signed in September 1954 in Manila , Philippines . The formal institution of SEATO was established on 19 February 1955 at ...